19% are still "neutral" on Joe Biden. He's benefiting so much right now from not being in the spotlight, he's practically the "not Trump" option on the ballot. Kind of a red flag for both of them that undecideds are going up.
Also, the white college grad sample is +18 Biden, when it was only +8 Dems in 2018 (matching the national margin). On the other hand, undecided/other skews toward young people and Latinos, undoubtedly anti-Biden liberals. It's hard to tell whether the remaining amount of bitter Sanders supporters will eventually vote for Biden, or if many of them actually will sit out or vote Green/Libertarian.
I suspect MOST of them will vote for Biden. Most did for Clinton last time, and that primary was even more contentious, bitter, and drawn out. Bernie personally likes Biden more, clearly, and many of his supporters seem to at least hate him less than they did Hillary. They’ll come around. The fact that there are just fewer Bernie supporters this time will help too, as will the fact that Bernie dropped out sooner and is likely to do more to help Joe. Seems to be that there just are not nearly as many “Anyone but Joe” voters coming from either the left or right as there were “Anyone but Hillary” voters. Which could be enough.
